Hammer mfg



F. w. MEYER.

CONTROL MEANS FOR ELECTROMAGNETIC HAMMERS AND THE LIKE.

APPLICATION FILED MAR. I8, 1918.

1,433,962. v Patented Oct. 31, 1922.

v Patented Oct. 31, 1922.

UNITED STATES PATENT. OFFICE.

FRIEDRICH W. MEYER, OF MILWAUKEE, WISCONSIN, ASSIGNOR TO THE CUTLER- HAMMER MFG. CO., OF MILWAUKEE, WISCONSIN, A CORPORATION OF WIS- CONSIN.

CONTROL MEANS FOR ELECTROMAGNETIC HAMMERS AND THE LIKE.

Application filed March 18, 1918. Serial No. 223,199.

To all whom it may concern:

Be it known that I, FRIEDRICH W. MEYER, a citizen of the German Empire, residing at Milwaukee, in thecounty of Milwaukee and State of Wisconsin, have invented new and useful Improvements in Control Means for Electromagnetic Hammers and the like, of which the following is a full, clear, concise, and exact description, reference being objects to provide control apparatus which will minimize the self inductive effects of such devices and provide for a substantial increase in the efiiciency thereof.

A further object is'to provide control apparatus which will enable operation of the controlled device on either alternating or direct current.

Other objects and advantages of the invention. will hereinafter appear.

The accompanying drawing illustrates certain embodiments of the invention and the same will now be described, it being understood that the invention is. susceptible of various modifications.

In the drawing,

Figure 1 shows diagrammatically control apparatus for a device supplied from an alternating current circuit.

'Fig. 2 shows diagrammatically apparatus for controlling a device supplied from a direct current circuit; and,

Figs. 3 and 4 show certain curves hereinafter explained.

Referring to Fig. 1, the same shows an electromagnetic hammer of conventional form which briefly described comprises a casing 1 having a central tubular portion 2,

y a tool 3 reciprocably mounted in said tubular portion, an electromagnetic winding 4 surrounding said tubular portion and a pivoted armature 5 to be attracted against the action of a spring 6 for imparting blows to the tool 3. And here itmay be noted that if such a hammer be supplied as in the past, with an alternating current of sine wave form by a dynamo provided with slip rings to complete circuit during one cycle and to interrupt circuit during the succeeding one or two cycles, the self induction of said ham mer will curtail the force of its blows as depicted in Fig. 3. In said figure e represents the electromotive force curve of sine form, 2' the current curve which tends to follow the electromotive force curve but which drops off abruptly upon attraction of the armature and B the consequent magnetic field curve: Thus the maximum energy or induction is available for only a small fraction of each stroke of the hammer with a consequent curtailment of the force of its blows. On the other hand, a magnetic field such as depicted in Fig. 3, heats the hammer to practically the same degree as would a magnetic field of constant value throughout each stroke since the heating is mainly due to hysteresis losses in the iron which are directly proportional to the maximum induction per cycle and the control means now to be described provides for increasing the effipiency of the hammer by increasing the duration of maximum induction during each stroke.

Such control means comprises a transformer T, an electroionic device 7, a small alternating current generator G and batteries 8 and 9. The transformer T has a primary comprising delta connected windings 10, supplied by a three phase circuit L and a secondary comprising star connected windings 12, 13, 14, 15, 16 and 17 to producea six phase current. The electroionic device 7 23, each connected to one of the secondary coils of transformer T and with a cathode 24 heated by current from battery 9 and connected by conductor 25 to one terminal of the hammer winding which has its other ter* minal connected by conductor 26 to the star point at the secondary of said transformer. Thus "the hammer winding is arranged to be supplied with current by the transformer T but only through said electroionic device which inherently functions as a rectifier and discharges under the control of an auxiliary anode orgrid 27. The grid 27 is connected to the cathode 2a and the battery 3 and genis provided with anodes 18, 19, 20, 21,22 and its erator G are included in circuit therebetween, the battery to supply a positive potential electromotive force of any desire Wave form whereby the electroionic device, due to its relay effect, may be caused to produce for example, F., current and induction curves such as illustrated in Fig. 4 wherein e designates the E. M. F. curve, 6 the current curve and 'B the induction curve. And with such curves maximum induction is quickly obtained at the commencement of each stroke and maintained until the stroke is practically completed with a consequent material increase in eiliciency. On the other hand different curves may be readily obtained by influencing the sensitive circuit of the electroionic device inv other Ways. Moreover the generator afiords control of the number of blows imparted by the hammer per unit of time since the frequency of the current pulses sup lied to the hammer may be varied by mere y varying the speed of said generator.

Referrin to Fig. 2,. the same shows schematica y a modified electromagnetic hammer comprising a magnetic frame 30, a tool 3]. reciprocable therein, an armature member 32 attached to said tool and electromagnetic windings 33 and 34 to attract said armature member in opposite directions. The winding 33 is arranged to attract the armature member for causing the tool to impart blows while the winding 34 is arrangedto attract the armature member for retraction of the tool, thus functioning as the spring 6 of Fig. 1. Also, this figure shows a direct current supply circuit L and electroionic control means for both windmgs. v

The control means comprises an electroionic device 35, batteries 36, 37 and 38 and an alternating current generator G1. The electroionic device comprises a single cathode 39 heated by current delivered by battery 36, two anodes 40 and 41 arranged on opposite sides of said cathode and two auxiliary anodes or grids 42 and 43 each into?- I posed betweenone ofsaid anodes and said cathode. Thecathode 39 is connected by conductor 44 to one side of the supply cir-" wit, and anode 40' isconnected by conductor 45 through the hammer winding 33 by conductor 46 to the other side of said supply circuit, while anode 41 is connected by concathode and for supplying current to the winding 34 when said device discharges between anode 41 and the cathode. However, the device is designed to discharge only when given positive potentials are impressed upon its grids by the batteries 37 and 38 subject to control by the generator G1 which opposes the potentialsof said batteries. The generator in this instance has a continuous slip ring 49 connected to the cathode and half insulated slip-rings 50 and 51 which are respectively connected to the grids 42 and 43 through batteries 37 and 38 respectively. And the slip ring arrangement is such that the potential half waves sup-plied by the generator oppose the potentials of batteries 37 and 38 alternately for causing the grids to be alternately subjected to positive potentials.

Thus in operation the electroionic device will first discharge between one anode and the cathode and then between the other anode and the cathode thereby energizing the hammer windings alternately. And said electroionic device will function as previously described to insure substantially rectangular induction curves for the hammer windings for a high degree of efficiency thereof. Moreover, as in the previous instance, the generator may be designed to afford the desired periods for reverse strokes of the hammer and may be varied in speed to vary the number of strokes of the hammer per unit of time.

What I claim as new and desire to secure by Letters Patent is:

1. The combination with an electromagnetic reciprocating device. of electroionic means in circuit therewith and including regulable means for controlling. the instantaneous values of' E. M. F. impressed on said device to increase the effective value of the magnetic field of said reciprocating device for a given amplitude thereof.

2. The combination with an electromagnetic reciprocating device, of means for supplying an intermittent pulsatory current to said device, said means including regulable electroionic means through which such current is passed-to said devicefor control of the. form of themagnetic field curve of said device.

3. The combination with an electromagnetic reciprocating device having an iron clad magnetic circuit, of means for supplying an intermittent pulsatory current tosaid means controlling the instantaneous values device, said means including regulable of E. M. F. impressed on said device to render themagnetic field curves thereof substantially rectangular.

LThe combination with an electromagnetic reciprocating device, of means to supply an intermittent pulsator current to said device, said means inclu ing regulable electroionic means controlling the instantaneous values ,of E. M. F. impressed on said device to render the magnetic field curves thereof substantially rectangular.

5. The combination with an electromagnetic reciprocating device, of a supply circuit therefor and electroionic means contolling the current supplied to the operating winding of said device to render the same of an intermittent pulsatory character, said means being regulable to vary the E. M. F, curves of the current pulses supplied thereby to said device.

6. The combination with an electromagnetic reciprocating device, of a supply .circuit therefor, electroionic means controlling the current supplied to the operating winding of said device to render the same of an. intermittent pulsatory character and means controlling said electroionic means to vary the E. M. F. curves of the current pulses supplied to said device through said electroionic means. I

7 The combination with an electromagnetic reciprocating device, of an electroionic device in circuit with the operating winding thereof, said electroionic device having a sensitive circuit and means for supplying an intermittent E. M. F. to said sensitive circuit.

8. The combination with an electromagnetic reciprocating device, of an electroionic device in circuit with the operating winding thereof, said electroionic device having a sensitive circuit and means for impressing an intermittent E. M. F. on said sensitive circuit and varying the frequency of such E. M. F.

9. The combination with an electromagnetic reciprocating device, of a supply'circuit therefor, an electroionic device connected between the operating winding of said reciprocating device and said supply circuit and means controlling said electrolonic device to effect an intermittent discharge thereof and to control the wave shape of the pulses of current passed to said winding.

10. The combination with an electromagnetic reciprocatin device, of a supply circuit therefor, an e ectroionic device connect ed between the operating winding of said electromagnetic device and said supply circuit and an alternating current generator controlling said electroionic device to efiect an intermittent discharge thereof and for controlling the wave shape of the pulses of current passed thereby.

In witness whereof, I have hereunto subscribed my name.

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